Automatic transmission fluid serves many functions in a modem automatic transmission. Pressurized fluid may be used to engage friction clutches in order to establish a power flow path with a desired speed ratio. Fluid lubricates gears and bearings. Excess heat is removed by fluid flowing over various components. When the fluid contains contaminants, it may be less effective in these functions and may cause failures such as stuck valves. Therefore, transmissions often include fluid filters. The fluid typically drains to a sump due to gravity. A transmission pump draws fluid from the sump and delivers pressurized fluid to a valve body, which distributes the fluid to various places within the transmission at pressures appropriate to the various functions.